Hazardous Location Ratings Overview

Introduction

Hazardous locations are defined by the National Electrical Code (NEC) as areas "where fire or explosion hazards may exist due to flammable gases or vapors, flammable liquids, combustible dust, or ignitable fibers or flyings."

Underwriters Laboratories Inc. (UL) tests and certifies equipment for hazardous locations based upon their ability to protect users from specific environmental hazards. Hazardous locations are classified depending on their type, condition, and nature.

UL offers a full technical summary for hazardous locations:

The following Hope Industrial Systems products have been tested and certified for hazardous locations:

Model No.

Description

Hazardous Location Rating

HIS-ML17-xxHG 17" Panel Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Class II, Division 2 for
Groups F, G; Class III; Temp Code T5
HIS-ML19-xxHG 19" Panel Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Class II, Division 2 for
Groups F, G; Class III; Temp Code T5
HIS-ML19-xxUG 19" Panel Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Class II, Division 2 for
Groups F, G; Class III; Temp Code T4A
HIS-UM17-xxHG 17" Universal Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Class II, Division 2 for
Groups F, G; Class III; Temp Code T5
HIS-UM19-xxHG 19" Universal Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Class II, Division 2 for
Groups F, G; Class III; Temp Code T5
HIS-UM19-xxUG 19" Universal Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Class II, Division 2 for
Groups F, G; Class III; Temp Code T4A
HIS-RL17-xxHG 17" Rack Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Temp Code T5
HIS-RL19-xxHG 19" Rack Mount LCD Monitor Class I, Division 2 for Groups A, B, C, D; Temp Code T5
KB-R2-xxx (all models) Full-Travel Keyboards Class I, II, & III, Division 2, Groups A, B, C, D, F, G; Temp Code T5
KB-M2-xxx (all models) Short-Travel Keyboards Class I, II, & III, Division 2, Groups A, B, C, D, F, G; Temp Code T5
KVM2EXT-xxx External KVM Extenders Class I, II, & III, Division 2, Groups A, B, C, D, F, G; Temp Code T5

HIS-ML17, HIS-ML19, HIS-RL17, and HIS-RL19 are all certified for Class I hazardous locations under UL File No. E328481.

HIS-ML17 and HIS-ML19 are certified for Class II & III hazardous locations under UL File No. E328481.

HIS-UM17, HIS-UM19, KB-R2 and KB-M2 keyboards, and KVM2EXT are all certified under UL File No. E334953.

KB-xx-EXT and KVM2EXT-xxx models are only certified when used with a Universal Mount Monitor.

Hope Industrial Systems provides wiring and conduit that complies with the U.S. National Electric Code but cannot rate wiring or conduit methods for hazardous locations, as these must be locally inspected and approved. The customer must install their hazardous location rated monitor in accordance with the applicable electrical codes for their location. More on hazardous location ratings.

YB, PED4X4, and FPED series are not approved for routing internal cables in Class II or III locations. If these mounting options are desired, customer must route cables outside of pedestal.

Choose only CP-CON-xx or CP-BLNK-xx cover plate series for Universal Mount Monitors for hazardous locations.

Hazardous Location Types

  • Class I - locations where flammable gases or vapors may be present in the air in sufficient quantities to be explosive or ignitable.
  • Class II - locations made hazardous by the presence of combustible dust.
  • Class III - locations where there are easily-ignitable fibers or flyings present, due to the types of materials being handled, stored, or processed.

Hazardous Location Conditions

  • Division 1 (Normal Condition) - the hazard would be expected to be present in everyday production operations or during frequent repair and maintenance activity.
  • Division 2 (Abnormal Condition) - the hazardous material is expected to be confined within closed containers or closed systems and will be present only through accidental rupture, breakage or unusual faulty operation.

Nature of Hazardous Substances

  • Class I Groups - Groups A (acetylene), B (hydrogen), C (ethylene), and D (propane). These materials are grouped according to the ignition temperature of the substance, its explosion pressure, and other flammable characteristics.
  • Class II Groups - Groups E (metal dusts), F (carbon dusts), and G (grain dusts). These materials are grouped according to the ignition temperature and the conductivity of the hazardous substance.
  • Class III Groups - These materials include wood-working and textiles that are easily ignitable, but not likely to be explosive.